a-a a-b aaa aab aah aak aao ab- aba abb abh abk abo aha ahb ahh ahk aho aka akb akh akk ako aoa aob aoh aok aoo baa bab bah bak bao bba bbb bbh bbk bbo bha bhb bhh bhk bho bka bkb bkk bko boa bob boh bok boo haa hab hah hak hao hba hbb hbh hbk hbo hha hhb hhh hhk hho hka hkb hkh hkk hko hoa hob hoh hok hoo ka- kaa kab kah kak kao kba kbb kbh kbk kbo kha khh khk kho kkb kkh kkk koa kob koh kok koo oaa oab oah oak oao ob- oba obb obh obk obo oha ohh oho oka okb okk oko oo- ooa oob ooh ook ooo